1. Field of the Invention
The disclosures herein generally relate to film deposition apparatuses, and particularly relate to a film deposition apparatus that forms a film on a substrate by supplying reactant gases through reactant gas nozzles in a vacuum container.
2. Description of the Related Art
A certain type of film deposition method used in semiconductor manufacturing processes supplies at least two types of reactant gases in sequence to a surface of a semiconductor wafer (hereinafter referred to as a “wafer”) serving as a substrate in vacuum atmosphere to form a film. This method repeats plural cycles, each of which causes a first reactant gas to be adsorbed to a surface of a substrate, for example, and then switches the supplied gas to a second reactant gas to form one or more layers of atoms or molecules through reaction of these two gases on the wafer surface. The repetition of cycles creates layers one over another thereby to form a film on the wafer. Such a process is referred to as the ALD (Atomic Layer Deposition) or MLD (Molecular Layer Deposition). This process can control a film thickness with high precision by adjusting the number of cycles. High homogeneity of film quality over the extent of the surface is obtainable, thereby helping to create a thin semiconductor device.
Such a film deposition method may be preferred when forming a highly dielectric material for use as a gate oxide film, for example. When forming a silicon oxide film (i.e., SiO2 film), for example, bis-tertiary butyl amino silane (hereinafter referred to as “BTBAS”) may be used as a first reactant gas (i.e., source gas), and ozone gas may be used as a second reactant gas (i.e., oxidant gas).
Patent Documents 1 through 8 disclose apparatuses for practicing such a film deposition method. A general configuration of these apparatuses is as follows. In a vacuum container, a platform to support a plurality of wafers placed thereon in a circumferential direction (i.e., rotational direction) is provided. Further, a plurality of gas supply units for supplying process gases to the wafer is situated in the upper space of the vacuum container to face the platform.
The vacuum container is depressurized to a predetermined process pressure, with the wafers placed on the platform. The platform is then rotated relative to the gas supply units around a vertical axis while the wafers are heated. The gas supply units supply two or more different types of gases, e.g., the first reactant gas and the second reactant gas as previously described, to surfaces of wafers. Physical barrier walls or air curtains made by discharging inert gas are provided between gas supply units that supply the reactant gases. With this arrangement, the process area formed by the first reactant gas and the process area formed by the second reactant gas are isolated from each other in the vacuum container.
In this manner, plural types of reactant gases are simultaneously injected into a single vacuum container, and respective process areas are isolated from each other to prevent the reactant gases from being mixed on the wafers. Any given wafer that revolves around a center point is subjected to the first reactant gas and to the second reactant gas in sequence while going through the barrier walls or air curtains, thereby allowing the film deposition process to be performed thereon.
Maintenance work of the vacuum container is generally performed by opening a top panel of the vacuum container. This requires the reactant gas pipes to be disconnected from the top panel, which complicates the maintenance work. When reactant gases have left residuals inside the pipes, these residuals may fall due to the manual handling of the pipes, which may end up being undesirable particles.
A preparatory treatment such as a heating process or plasma process may be performed with respect to reactant gases before supplying the reactant gases to the vacuum container. To this end, a preparatory treatment unit to perform the preparatory treatment may need to be provided in the vicinity of the vacuum container, i.e., may need to be placed on the top surface of the top panel. Since such a preparatory treatment unit is generally bulky and heavy, an elevation mechanism for lifting the top panel ends up requiring a large amount of power. Further, there is also a need to secure sufficient space over the vacuum container such that the top panel plus the preparatory treatment unit can be lifted without any obstacle. This limits the choice of location where the apparatus is installed.
Accordingly, it is preferable to provide an arrangement for allowing easy maintenance work of a film deposition apparatus in which a rotary table to support wafers placed thereon is rotated in a vacuum container to revolve the wafers, which are subjected to a film deposition process performed by reactant gases supplied through reactant gas nozzles.
[Patent Document 1] U.S. Pat. No. 6,634,314
[Patent Document 2] Japanese Patent Application Publication No. 2001-254181: FIG. 1 and FIG. 2
[Patent Document 3] Japanese Patent No. 3144664: FIG. 1, FIG. 2, claim 1
[Patent Document 4] Japanese Patent Application Publication No. 4-287912
[Patent Document 5] U.S. Pat. No. 7,153,542: FIG. 8(a), (b)
[Patent Document 6] Japanese Patent Application Publication No. 2007-247066: paragraph 0023-0025, 0058, FIG. 12, and FIG. 18
[Patent Document 7] United States Patent Application Publication No. 2007-218701
[Patent Document 8] United States Patent Application Publication No. 2007-218702